Services such as Google Maps (maps.google.com) allow users to conduct searches that are limited to particular geographic areas. For example, while viewing a street or satellite map of New York City on a web browser such as Google Chrome, a user may search for the word “pizza”. In response, the servers cause the user's computer to display icons indicating the positions of listings that match the query, such as restaurants that have “pizza” in their name.
The results of the query may be sent in a way that permits a great deal of interactivity. For example, the map is sent as tiles of images and descriptions of the results and their positions are sent as text (such as data formatted as JSON (Javascript Object Notation) or HTML). This allows the user's computer to display icons on the map and a text listing of the results next to the map. Using Javascript provided by the server, the client computer can determine whether the user has clicked an area of the map occupied by an interactive icon and perform a number of actions in response, such as displaying a balloon containing even more information about the listing.
Google Maps also permits layers. For example, it is capable of showing icons for entries on Wikipedia.org that are associated with latitude/longitude coordinates matching the geographic area currently being viewed (e.g., http://en.wikipedia.org/wiki/Wikipedia:WikiProject_Geographical_coordinates). The icons of entries are sent as an image to be overlaid on the map, along with information relating to the entries. The information is sent in JSON with information identifying the entry's position on the map and an identification of the entry. The position information may be used by the user's computer to determine whether the user actuated the icon (such as by clicking it or hovering a mouse cursor over it) and the identification information may be used to obtain more information from a server if the icon is actuated. YouTube results may also be shown as a layer. These results are not filtered based on the query but, rather, show all entries in the area covered by the map.
Google Maps also features a “Places of Interest” layer that allows users to display icons associated with all businesses falling within certain pre-selected categories sent by the server, such as “Italian” and “Pizza” restaurants, banks, gas stations, and the like. Although the user may collectively display search results from the pre-selected categories and from searches based on custom search terms that are not pre-selected, the results are separate, i.e., the preselected category icons do not change based on the user-defined term and vice versa. For example, the user may check a box next to “pizza” and type in the term “vegetarian”, in which case Google Maps combines and displays the search results together; however, the results associated with “pizza” are not selected based on the “vegetarian” query nor are the results associated with the “vegetarian” query selected based on the selection of “pizza” from the list. Sites such as www.tavernoxoros.gr (showing many locations on a map in response to a user's selection of pre-selected categories) and www.smalltownbrooklyn.com (which may be capable of showing all businesses on a map) are similarly able to show all results associated with pre-selected categories.